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Crank bolt

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amrbose14

New member
Apologies for the idiot question:

Whats a safe and sensible way to check the crank bolt is tight? I have the car up on one axle stand so I can get to it - and the car is in gear. Turning clockwise rotated the engine slightly and took the slack up. Presumably it is safe for the engine to apply so clockwise force to the bolt in this state? Which sill leaves me with the question of how safe it is to lie under it whilst doing this!

Chris
89 944 turbo.
 
Is there anything that suggests you it might not be tight enough?

This is not an idiot question at all but at my humble level of knowledge I must say I only have an idiot answer to give you - I see no other way than loosening it (while blocking the engine with a tool on the starter ring gear in place of the starter motor, the special tool being very good to avoid damage to the ring gear) then retighten it to the torque indicated in the workshop manual.
By the way this is the highest torque figure I came across in the manual, and you may well need a "big" torque wrench.
 
Can you not do it from above with the car on the ground? On an S2 there's access to do it with all four wheels on the ground, the worst that'll happen is that the car will nudge your shins if it's in gear. I'm always wary of applying big torque to things that could fall on me, plus I'd probably struggle to apply enough force while lying under the car.

You'll need to lock the crank somehow as the springs in the clutch will muck up your torquing (not sure if this applies to turbot clutches though). I used a cold chisel in the ring gear through one of the access holes in the flywheel to loosen and tighten although this is obviously a bodge so use at your own risk..
 
Thanks guys. It looked to me like there was not enough room to get down to it from the top but I shall have another look.

I'm not sure I need to retorque it, but as for why: recently something funny happened and I've now got a lower oil pressure at idle (~1.5bar). Seems fine at higher revs though. It's off to Promax on Thursday but they suggested I checked the crank bolt was tight. I would imagine that if it feels 'good and tight' to me with the car in gear then it is unlikely to be the source of the low oil pressure.

Chris

p.s. Hey Elvis - we are neighbours. I live in Beeston.
 
What ever you do, can i suggest that you really don't leave the wrench on the bolt. You would think that only a real idiot would do this [:(][:(][:(][:(]

It was on an MX5, and it did and halve make a lot of noise when i started it up. the bolt just dropped out the front of the crank, having threaded the crank (which surprised me, i would have thought it would just sheer off), not the best trick in the book, and not the cheapest to get fixed.
 
Hi Chris, yours isn't black with a personal plate on is it? I'm in Beeston as well and I walk/drive past a black one most days.
 
Wow... fancy that.

Nope - but I think I know the one you mean. An A reg with D90 wheels, not much in the way of decal but an S2/turbo bodykit. Wheels look like they have a wider track than mine.

Anyway, mine is dark blue (nautic?) D reg. Mostly lives in the garage as I cycle to work.
 
Small world... Mine's the white S2 in my profile pic to the left, although it's currently in for surgery at Stallion opposite the Vic as the sills/wings were rapidly vanishing.
 
Oh... is that place good then? Nice to know they will have some experience of working on 944s if I ever need then (and with my sills I will).

Anyway... on the crank bolt front I've managed to get a socket on it (24mm deep) from under the car whilst its on the ground (quite a fiddle). On my turbo the air box is directly above the crank which makes getting to it from above impossible.

However, I'm even more confused as I can easily turn it, together with the belts etc, even though the car is in gear on the ground - at least it seems to be as I took the handbrake off and pushed it forward as far as I could. Presumably that sounds like the car is just not in gear for some reason, rather than being a sign that the crank bolt is loose?
 
Car looked really good in primer when I went to see it at the w/e, just waiting for the paint now. They're a ferrari specialist and my 944 is by far the cheapest car in there (there's normally some nice stuff parked out there at the weekends..) so hopefully they know what they're doing.

If the car is in gear then you'd struggle to push it more than a couple of feet as you'd be fighting the compression. Also, if it is in gear then you shouldn't be able to turn the engine (I assume this is what you mean by belts moving) without moving the car..

How 'easily' can you turn the bolt? I need a breaker bar on mine to turn the engine over by hand and and it's not easy at all, especially with the plugs in.

I've left the ratchet on as well, luckily in my case it just pinged off when the engine turned over and somehow managed to avoid everything expensive while doing so.
 
Do you know what the work is going to cost you?

There are two belts (power steering? + ??) that are exposed and when I turn the bolt these turn. I can do this quite easily from under the car. No need for a breaker bar!! I've had another look at manuals etc. and I don't think I can possibly be the wrong bolt. I don't know if the compression on a turbo is sufficiently lower to explain the difference in force needed? Or is this symptomatic of a loose crank bolt? Maybe I should carry on turning it (clockwise when I'm facing the bolt) and see what happens...

Hmmm....
 
I just had a chat with a chap at Promax.. sounds like the engine is simply not on a compression stroke, and not in gear. The fact that the belts turn with the bolt probably indicates that it is tight. Shame really... means the low oil pressure is due to something else!
 
Don't be too hasty to assume that the bolt is not the cause of low oil pressure ... the oil pump takes significant force to drive it at speed as the amount of energy required to pump large quantities of oil at high pressure is significant. Therefore the bolt may be tight(ish) but still allow the pump drive to slip.

If you can, lock the engine (using a locking tool or something else - cold chisel-type method) and ensure that the bolt is torqued as it should be. It is listed as 'effing tight'* for a reason ...


Oli.

* - That's the technical term for about 250,000 nM.
 
ORIGINAL: amrbose14
The fact that the belts turn with the bolt probably indicates that it is tight. Shame really... means the low oil pressure is due to something else!
Click to expand...

If the crank bolt was not tight enough you may also have a poor oil pressure at anything other than idle, but it doesn't seem to be the case?
What kind of oil grade is in the car at the moment and what oil pressure do you get under load? What is oil consumption like and does your car smoke?
 
Oil pressure seems to be pretty normal through the revs - although if it was low by a similar amount to at idle (~0.5 bar) then would I notice? And it is high when the engine is cold. The engine does not appear to be using oil (and generally it doesn't) but checking again is a good idea (!). I've not noticed any smoke either.

Hopefully I'll make it down to Milton Keynes tomorrow and then we shall see what is what...

thanks for the help guys - I'll let you know what happens.

p.s. Elvis - perhaps a few jars at the Vic sometime?
 
Good news.... mostly. There was a small piece of metal (!) wedged in the oil pressure release valve. That removed oil pressure is excellent, now about 3 bar at warm idle. Seems to be running very well too.

The piece metal is another story... probably dating back to when a bolt shot out of (the inside of) the cam tower a little while ago. The only thing to do now is worry about a). whether there are any other bits of metal in there(!) b). what damage the bit of metal did elsewhere before ending up in the valve.

Elvis - will do. defn a pint in the near future.
 
Great news [:)]

Sounds like a good time to do a couple of regular oil and filter changes to make sure anything nasty is out of the system [:eek:]
 
Yup! Reckon I'll do one after ~1000 miles. Anyone used a magnetic sump plug? A friend of mine was singing it's praises for removing metal nasties.
 
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